In many types of machines different tools are coupled to and then uncoupled from the machine to accomplish different tasks. For example, a hoe excavator with a hoe arm may have a variety of buckets of various widths and shapes that are suitable for particular different tasks. Depending on the task, the desired bucket is coupled to the end of the hoe arm of the excavator, and when that task is finished the bucket will be uncoupled and a different bucket will be coupled to the arm to accomplish the next task. In addition to various buckets, other tools such as pneumatic hammers, post hole augers, and the like are often attached to the excavator arm to increase the variety of tasks that the machine may accomplish.
Changing the bucket can be time consuming and so various quick coupling mechanisms have been developed to reduce the time and effort required to couple various tools to the excavator arm. Often these tools are maneuvered in holes or like confined areas where people are working, and so it is necessary for such quick coupling mechanisms to secure the tool such that the tool cannot fall off accidentally, and further must secure the tool tightly to the end of the excavator arm such that undesirable loose movement of the tool with respect to the excavator arm is prevented and control is maintained.
U.S. Pat. No. 6,487,800 to Evans et al. discloses a quick coupler with a coupling bar that is moved by rotating threaded bolts to a closed and coupled position to secure the engagement of the end of an excavator arm to a tool, such as a bucket. U.S. Pat. No. 6,123,501 to Pisco and U.S. Pat. No. 4,214,840 to Beales also disclose quick coupler mechanisms.
Weldco-Beales Mfg. of Edmonton, Alberta, Canada uses a double acting hydraulic cylinder to move a wedge shaped coupling bar between open and closed positions. The operator must also leave the operator position and manually install a safety pin in order to ensure that the wedge is maintained in the closed position.